Presentation Abstract

Eelgrass (Zostera marina) monitoring and restoration is important to commercial and ecological management in the Salish Sea. In the southern Salish Sea (Puget Sound, WA), eelgrass distribution overall has not changed in acreage but local eelgrass habitats have declined whereas others have increased. Additionally, coexistence with non-native dwarf eelgrass (Z. japonica) motivates tracking the spatial patterns of change in distribution of both Zostera species on a seasonal and interannual basis. Past efforts to map eelgrass communities have involved the use of satellite imagery and imagery acquired from manned aircraft. Imagery acquired using these platforms typically has a spatial resolution ranging from ~30m to ~1 m. UAS technology offers a new approach to obtain imagery with a spatial resolution of a few centimeters, at very low cost and the image acquisition can be carefully timed to take advantage of low tides. The Padilla Bay National Estuarine Research Reserve (PBNERR) includes one of the largest expanses of eelgrass on the west coast, which has been monitored long-term along permanent transects for Z. marina and Z. japonica coverage, shoot density, and biomass. This provides an ideal setting for the evaluation of alternative methods for mapping eelgrass communities using UAS technology. During the summer of 2017, we collected imagery from a 200 m by 2500 m transect overlapping the permanent plots that make up the PBNERR long-term monitoring transect. We collected imagery using both a multirotor and fixed-wing UAS and two different camera systems with different spectral and spatial resolutions. Here we discuss the logistical challenges of conducting these surveys and present preliminary results of our image classification efforts.

Session Title

Structure from Motion and Drone Aerial Imagery for Coastal Restoration and Management

Keywords

Mapping eelgrass, Padilla Bay, Unmanned aerial system, UAS

Conference Track

SSE15: Data and Information Management

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE15-300

Start Date

4-4-2018 4:15 PM

End Date

4-4-2018 4:30 PM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 4th, 4:15 PM Apr 4th, 4:30 PM

Mapping eelgrass (Zostera sp.) habitat in Padilla Bay, WA, using an unmanned aerial system (UAS)

Eelgrass (Zostera marina) monitoring and restoration is important to commercial and ecological management in the Salish Sea. In the southern Salish Sea (Puget Sound, WA), eelgrass distribution overall has not changed in acreage but local eelgrass habitats have declined whereas others have increased. Additionally, coexistence with non-native dwarf eelgrass (Z. japonica) motivates tracking the spatial patterns of change in distribution of both Zostera species on a seasonal and interannual basis. Past efforts to map eelgrass communities have involved the use of satellite imagery and imagery acquired from manned aircraft. Imagery acquired using these platforms typically has a spatial resolution ranging from ~30m to ~1 m. UAS technology offers a new approach to obtain imagery with a spatial resolution of a few centimeters, at very low cost and the image acquisition can be carefully timed to take advantage of low tides. The Padilla Bay National Estuarine Research Reserve (PBNERR) includes one of the largest expanses of eelgrass on the west coast, which has been monitored long-term along permanent transects for Z. marina and Z. japonica coverage, shoot density, and biomass. This provides an ideal setting for the evaluation of alternative methods for mapping eelgrass communities using UAS technology. During the summer of 2017, we collected imagery from a 200 m by 2500 m transect overlapping the permanent plots that make up the PBNERR long-term monitoring transect. We collected imagery using both a multirotor and fixed-wing UAS and two different camera systems with different spectral and spatial resolutions. Here we discuss the logistical challenges of conducting these surveys and present preliminary results of our image classification efforts.